The present invention relates to a circuit for a brake system with traction slip control by brake management which includes wheel sensors to measure the wheel rotational behavior and electronic circuits to evaluate the sensor signals and to generate braking pressure control signals which are used to introduce braking pressure into the wheel brakes of the overspeeding wheel when a predetermined variable traction slip control threshold is exceeded.
A circuit of this type is disclosed in German patent application No. 40 17 845, for example. The traction slip of each driven wheel is controlled individually. The control threshold, in excess of which traction slip control commences, is variable in this known circuitry. The control threshold includes a predetermined basic value and a portion derived from the wheel slip acceleration. Suitably, a wheel slip value responsive to the vehicle speed is used as a basic value. To improve the starting behavior, the basic threshold founds on a relatively high initial value which decreases linearly with the vehicle speed and reincreases starting from a defined vehicle speed of, for example, 25 km/h.
The purpose of such a variation of the control thresholds, which determine the commencement of traction slip control, is to conform the traction slip control or the introduction of pressure into the wheel brake of the overspeeding wheel, in comparison to known control systems with invariable control thresholds, with a still greater accuracy to different road conditions, with the objective of improving the control quality.
German patent No. 37 41 247 discloses conforming the slip threshold values for a traction slip control system to the tires of an automotive vehicle.